[GreenKeys] Fw: BBC enquiry - telegraph machine

[Nick England]

I have two high speed paper tape code recorders
A Navy RD-110/U and a McElroy one.
Each has a single ink pen actuated by a single electromagnet in a permanent
magnet field (very similar to speaker voice coils) and are driven by tube
electronics.

There were many kinds of analog paper recorders, like the Brush recorders
with moving stylus on thermal paper.
I also remember some brand that had tiny galvanometer mirrors in glass tube
fixtures. You could get multiple channels of these directing a light source
onto a roll of photographic paper. Very high freq response because there
was no pen to wiggle, just a tiny mirror and reflected light beam.

Nick England K4NYW
www.navy-radio.com


On Thu, Jun 19, 2014 at 12:46 PM, WA5CAB--- via GreenKeys <
greenkeys at mailman.qth.net> wrote:

> Right.  The Undulator had what I knew as a pen motor or a galvonometer.
> But my question was, did it have only one, or more than one?
>
> Robert Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
>
> In a message dated 06/19/2014 11:21:58 AM Central Daylight Time,
> jhhaynes at earthlink.net writes:
>
> Let's keep in mind that there are two different flavors of paper tape
> code recorders.  The one used for Morse Code at ordinary speeds, and
> for recording telephone numbers and fire alarms, and often made by
> J. H. Bunnell, uses an electromagnet to make an ink mark on the tape.
> Or to emboss the tape.  The other kind, the undulator, is an analog
> recorder, that records the magnitude and direction of current, not
> simply whether the current is on or off.  That's what was used with
> ocean cable telegraphy.
>
>
> jhhaynes at earthlink dot net
>
>
>
>
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